The present invention relates to a surgical light apparatus, and particularly, to a support arm for the surgical light apparatus. More particularly, the present invention relates to a jointed support arm that permits movement of a lighthead of the surgical light apparatus to various positions and that counterbalances the weight of the surgical lighthead.
Surgical lights used in hospital operating rooms to illuminate surgical sites on patients are known. Many surgical lights include a surgical lighthead containing a light source and an arm mechanism configured to support the surgical lighthead relative to a ceiling of the operating room. Such arm mechanisms typically include one or more joints which allow the surgical lighthead to be moved in plural degrees of freedom within the operating room various positions so that the light source of the surgical light illuminates a surgical site on a patient in a desired manner. It is desirable for the arm mechanism of the surgical light to counterbalance the associated surgical lighthead when the surgical lighthead is at any position within a range of positions.
According to the present invention, an arm assembly for supporting a surgical lighthead of a surgical light apparatus includes a first arm and a first clevis appended to the first arm. The first clevis has a pair of separated first flanges. The first clevis further includes a first stop surface and a second stop surface. The arm assembly includes a second arm which is formed to include an interior region. The surgical lighthead is supported by the second arm. A second clevis is appended to the second arm and has a pair of separated second flanges. The second clevis further includes a third stop surface and a fourth stop surface.
A pair of pivot pins pivotably couple each of the pair of second flanges to a respective one of the first flanges so that the second arm and second clevis are pivotable about a main pivot axis relative to the first arm and first clevis. The pivot pins are spaced apart to define a gap therebetween. A rod extends within the interior region of the second arm. The arm assembly includes a link coupled to the rod and pivotably coupled to the first clevis for pivoting movement about a link pivot axis that is spaced apart from the main pivot axis. A spring extends within the interior region of the second arm and exerts a force on the rod and the link to counterbalance the surgical lighthead.
The arm assembly is configured so that the second arm and second clevis are pivotable about the main pivot axis relative to the first arm and first clevis between a first position in which the third stop surface engages the first stop surface to limit pivoting movement of the second clevis and second arm in a first direction and a second position in which the fourth stop surface engages the second stop surface to limit pivoting movement of the second clevis and second arm in a second direction. The link moves into the gap between the pair of pivot pins during movement of the second arm and second clevis between the first position and the second position.
In preferred embodiments, the arm assembly includes an adjuster mounted on the rod. The adjuster includes a spring-engaging portion that engages the spring to compress the spring against the second clevis. The adjuster is movable to change the force exerted by the spring on the rod and the link to counterbalance the surgical lighthead. Also in preferred embodiments, the arm assembly includes a space filler that is positioned to lie between the first flanges of the first clevis. The space filler includes a rim that spans the space between the first flanges. In addition, the rim of the space filler cooperates with the first flanges to span the space between the second flanges of the second clevis.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.